1.Hornos Rotatorios

Institute ™

Rotary Kiln Maintenance Seminar

Introduction

Institute ™Introduction 2

Introduction

Kiln Seminar Agenda Types of Kilns Systems The Clinker Production Process Terminology Kiln Safety


Kiln Seminar Agenda


Kiln Seminar Agenda

1. Introduction, Kiln Safety2. Kiln Shell3. Tires and Ovality4. Kiln Supports5. Kiln Bearings6. Kiln Drive7. Kiln Alignment8. Seals, Thrust Rollers,

Maintenance Schedule


Types of Kiln Systems


Pyro-processing System

The rotary kiln is part of the pyro-processing system.

4-Stage Preheater Calciner String

Calciner

Tertiary Air Duct Clinker

Cooler

Rotary Kiln

4-Stage Preheater Kiln String


SP ILC SLC

Preheater Arrangements

These are some of the many different configurations of preheaters that have been installed.


SP Preheater System

The SP (Suspension Preheater) system features four preheater cyclones. Most calcining is done inside the kiln. Some fuel (15%) may be added in the riser duct.

Fuel Consumption 800 Kcal/kg Clinker


ILC Calciner

The ILC (In Line Calciner) system adds a separate vessel for calcining. Up to 60% of total fuel may be added here. Raw meal entering the kiln is 92% calcined.



SLC Calciner

The SLC (Separate Line Calciner) system has two preheater strings, one string attached to the kiln and a second string with calciner attached to the tertiary air duct.



Wet Process System

In the wet process system, drying, preheating, calcining and burning are all done inside the kiln.



Rotax-2 Kiln

State of the art kiln technology

Two supports

production rates to 7500 mtpd

Tangential tire suspension

Gearless, friction drive

Self-aligning roller supports


The Clinker Production Process


Clinker Production

Limestone

Clay/Sand

Iron Ore

Clinker

CaCO3

SiO2 + Al2O3

Fe2O3

CO2

CaO

1650º F900º C

2650º F1450º C


Calcium Oxide CaO (C) 67%

Silicon Oxide SiO2 (S) 22%

Aluminum Oxide Al2O3 (A) 3.5%

Iron Oxide Fe2O3 (F) 3.5%

96%

Impurities 4%

100%

The Four Oxides of Cement Clinker

Clinker Production


Raw Materials

67% C

22% S

3.5% A

3.5% F

4% Impurities

100%

Clinker

67% C3S

14% C2S

5% C3A

10% C4AF

4% Impurities

100%

2650 ºF

1450 ºC

Clinker Production


Liquid phase

Free CaOCaCO 3

Quartz

Clays

C S2

C S3

C A3

C AF4

Clinker Production

Inside the kiln, the iron and alumina melt to form a flux in which the calcium and silica dissolve. Upon cooling the mixture crystallizes into clinker.


Terminology


Kiln Terminology

1 Rotation, as seen from discharge hood

2 For FLS and Fuller kilns, pier numbering starts at discharge end

3 Bearing right and left a seen from discharge end

Kiln Pier

Inlet Seal

Support Roller

Drive Pier

Kiln Shell

Discharge Hood

Inlet Hood

GearTire

Outlet Seal

Rotation1

Pier 1 2

Tertiary Air Duct

Pier no. 3 Right Uphill Bearing 3


1. Preheater Top Stage2. Downcomer Duct3. Kiln Seal4. Preheater Intermediate Stage 5. Preheater Intermediate Stage6. Preheater Lower Stage7. Rotary Kiln8. Induced Draft Fan9. Kiln Burner10. Clinker Cooler11. Cooler Vent System

System Terminology


Kiln Safety


Preheater Flush

Never work anywhere on a kiln system while a preheater vessel is plugged. If the plug breaks free it will rush like water through the system, burning everything in its path.


Preheater Flush

These men were working inside a kiln when a preheater flush occurred. Two fatalities resulted.


These men were working outside a clinker cooler when a preheater flush occurred, spewing hot material through an open man-door. Two fatalities resulted.

Preheater Flush


Protective Clothing

When working with hot dust a complete fireproof suit must be worn.


Hot Dust

Hot dust can unexpectedly blow out through any opening in the system. Keep doors and ports closed! Hot dust can ignite flammable materials in the area.


Dust Hazard

Be careful around kiln seals. Hot dust can blow out during process upsets. Kiln dust also contains lime, which can burn skin and eyes.


Dust Hazard

Know where your shower and eyewash stations are!


Fall Protection

Always wear your safety harness when working above ground.


Heights

High places can be dizzying. Always tie off with a safety belt.


Air Blasters

Air blasters are often placed near the kiln inlet and outlet. They must be disabled when working nearby.

Kiln Inlet Hood Cooler Inlet


Air Blasters

Discharge the Tank

Shut off the Air

Lock Out the Air Valve

Test That the Tank is

Empty


Lockout/Tagout

Follow your plant’s safety lockout procedures. Lock out all equipment affecting the area in which you are working.


Drive Guards

All moving parts must be completely guarded.


Roller Guards

Kiln rollers are nowadays completely guarded. Note that the old practice of running lead wire between tires and rollers to check alignment is no longer encouraged.


Coating Collapse

Do not work under loose kiln coating.


Kiln Rollback

Due to the feed material being dragged up one side of the kiln as it turns, an offset load exists which tries to make the kiln rotate backwards.

Load Center of Gravity


Kiln Roll-Back

The backstop can be released manually to allow the kiln to roll back. Warning! Rolling back too fast can explode the inching drive and cause serious injury. Keep a lock on the release switch to prevent unauthorized use.

Safety Padlock

Release Switch


Electrical Safety

When working inside a kiln make sure electrical cables do not short out on the kiln shell.


Rigging Safety

Before making heavy lifts, make sure you have received the necessary rigging training.


Carbon Dioxide

Carbon dioxide is a normal product of the biological process, but too much CO2 can kill.


Carbon Dioxide

Kiln exhaust gas contains approximately 35% CO2. This heavier-than-air gas tends to accumulate in low lying areas. Make sure all enclosed areas are properly vented before entering.


Combustibles

Lock out all fuel systems before entering the kiln.


Steam Explosions

Use of water around a kiln can be deadly. Water coming into contact with hot kiln feed or clinker can vaporize in an instant, causing a steam explosion. Especially, be careful around wet process kilns.


This man was working in a clinker transport tunnel when hot material flushed out into standing water in the elevator pit. He was killed by the steam explosion.

Steam Explosions


Questions?

Institute ™


Kiln Shell


Shell Details

Kiln Crank

Measuring Kiln Crank

Heat Correction of Kiln Crank

Shell Repair

Shell Welding

Submerged Arc Welding

Kiln Shell


Shell Details


Shell Details

Inlet Cone

Outlet Shroud

Tire No. 1

Tire No. 2

Tire No. 3

40 mm40 mm

40 mm (gear)

75 mm(under tire)

50 mm

30 mm 30 mm 30 mm

80 mm(under tire)

75 mm(under tire)

40 mm

Typical shell plate thicknesses.


Kiln Crank


Kiln Crank

Kiln crank occurs when a kiln shell is not perfectly straight. As the shell turns, cyclical loads and stresses occur in the shell and the kiln supports.


Kiln Crank

Kiln crank can cause severe cyclical loads, leading to shell cracks and fatigue cracks in the roller shafts.


Kiln crank will result in gear misalignment which can destroy gear teeth.

Kiln Crank


Kiln Crank

Kiln crank can be temporary, as in the case of a rain warped shell, or permanent, as in the case of a shell damaged by heat blisters.


Kiln Crank

When a hot kiln is stopped during a heavy rainstorm, one side of the shell cools off and contracts, causing a concave up curvature.


Kiln Crank

When a hot kiln is stopped too long without rotation, heat will rise and the top of the shell will expand, causing a convex-up curvature.


Kiln Crank

Irregular coating formation or refractory wear can cause one side of the shell to heat up more than the other. The result is a temporary crank in the shell.


Kiln Crank

Damaged refractory will cause a hot spot in the shell.


A hot spot left unattended will wrinkle the shell and create a crank. Refractory bricks will no longer stay in place and the shell section will have to be replaced at great expense.

Kiln Crank


Heat Damaged Kiln Shell

A heat-wrinkled kiln shell will also shorten the kiln, causing tires to run off-center.


Kiln Crank

Kiln crank can be caused by poor alignment of kiln sections during assembly or repair.


Kiln Crank

Kiln crank can be caused by weld shrinkage at a temporary shell patch.





Kiln crank can be identified by measuring roller deflection. The load on the roller will change as the kiln turns and this results in bending of the roller shaft.


A roller that deflects cyclically with kiln rotation by over 0.3 mm typically indicates a crank in the shell that should be repaired.




Kiln crank can be measured by measuring shell run-out. A polar diagram is generated on which the deviation from the true kiln center can be seen.


A series of polar diagrams gives a picture of the shell crank.






A kiln shell can sometimes be straightened by heat correction. Insulation is wrapped around the shell, allowing the shell steel to overheat. Shell stresses then diminish as the kiln sags into place on the rollers.


Temperature sensors are installed to carefully monitor shell temperatures beneath the insulation during the correction process.





Shell Repair


Shell Repair

Major shell defects are normally repaired by replacing the damaged section. The band-aid approach is at best a temporary solution.


Field Joint Hardware

New shell sections are joined with adjustable erection lugs.


Shell Alignment

By adjusting the erection lugs the shell sections are straightened until a perfect centerline is achieved.


Tire Handling


Shell Rigging


Shell Rigging


Shell Handling


Spider Bracing


Spider Bracing


Spider Bracing


Shell Stiffening Rings

Many older kilns had shell stiffening rings. These rings would eventually cause shell cracks due to heat expansion. Field-cutting expansion slots may help this problem.


Shell Welding


Joint Preparation

Prior to welding the shell plate ends are carefully prepared.


Weld Shrinkage

The 60º double V weld results in less shrinkage and less weld metal being required. Weld distortion is minimized, avoiding the “gull-wing” effect.


Weld Shrinkage


Shell Welding


Shell Welding

After completing the outside weld, the root pass is removed using carbon arc gouging.


Shell Welding

After gouging, the joint is carefully cleaned and inspected to ensure that no defects from the root pass remain.


Shell Welding

When welding is finished, the joint is inspected radiography or ultrasound. Defects are marked and then repaired.





































Institute ™


Tires and Ovality


Tires and Ovality Tires and Tire Mounting Tangential Suspension Tire Clearances Ovality Tire Creep and Top Clearance Correcting Ovality Tire Pad and Stop Block Repairs Tire Crack Repair


Tires and Tire Mounting


Kiln Tire Support System

Tires are mounted over support pads with machined O.D.’s. Precise clearances are maintained to allow for different rates of expansion between kiln tire and kiln shell.

Machined SurfaceMachined

Surface


Pads are not welded to the shell, but are trapped in place by guide bars. Stop blocks are welded on one side only, alternating from one side to the other.

Tire Attachment


Tire Attachment

A loose stop ring is placed between the stop block and the tire. Wear takes place on the replaceable ring, not on the stop blocks.

Stop Ring

Stop Block

Guide Bars

Machined Support Pad


Tire Attachment

This shows a slightly different version of the floating pad, stop ring design.


Bolted Support Pads

Some FLS kilns have bolted support pads. Bolting avoids heavy welds which lead to shell cracks. The above arrangement uses a wear ring between stop blocks and tire.


Bolted Support Pads

This arrangement for smaller, light duty kilns uses stop blocks directly against the tire, i.e., without the use of wear rings.


On kilns without wear rings, when the blocks eventually wear down, they have to be cut off and new ones re-welded.

Tire Attachment


Tangential Suspension



The tire is fixed and does not creep inside the shell. Shell expansion is accommodated with a system of spring-loaded wedges.



Tangential suspension reduces ovality. Forces on the shell are tangent rather than radial.



Brackets are bolted onto the tire. “Dog bones” keep the tire in position. Wedges keep the brackets tight against the dog bones. Springs keep the wedges tight as dimensions change with heat expansion.

Tire Bracket

“Dog Bone”

Wedge

Spring



Tire Bracket“Dog Bone”

Wedge

Spring Rod

Wedge Retainer



A completed tire section ready for installation.



Wedges are held in position with retainer brackets bolted to the top of the “dog bones”.



The spring rod pushes the wedge in to maintain a tight fit between dog bones and brackets as the kiln shell expands and contracts.



As the wedges wear, the spring length increases. Periodically, check the distance and adjust the spring tension as required.



“Dog bones” are attached to the shell with heavy welds. Periodically inspect the welds for cracks.



Tire bolts are hydraulically tightened to specification.


Hydraulic Bolt Tensioning Tool


Tire Clearance


Tire Clearance

Tires are mounted over support pads with machined O.D.’s. Precise clearances are maintained to allow for different rates of expansion between kiln tire and kiln shell.

Machined Surface


Tire Clearance

It is necessary to have clearance between the tire support pads and tire I.D. to accommodate heat expansion of the shell. Cold clearance is typically 6-12 mm for a new kiln, depending on the location of the tire.

Normal Cold Clearance


Tire Clearance

The shell will heat up faster and expand more than the tire, and clearance will diminish. Normal hot running clearance should be from 0 to 3 mm (⅛”).

Normal Hot Running Clearance, 0-3 mm


Rate of Expansion

Example. A kiln shell with 5 meter (5000 mm) diameter at 20º C is heated to 320º C. The shell expands

5 meters x (320 - 20) = 15 mm

100

Rule of Thumb

Expansion of Steel (approx):

1mm / Meter/ 100ºC


Ovality

A kiln shell is not stiff enough to support its own weight. When placed on the ground it collapses to an oval shape.


Ovality

When placed inside a rigid tire the shell’s deformation is reduced, but it will still collapse if there is any clearance present. The amount it collapses depends on the amount of clearance and on the stiffness of the shell.


Shell and Tire Deformation

Shell deformation also occurs because the tire is not absolutely rigid. Due to elasticity of both shell and tire, the actual top clearance is 1.5 to 2 times the difference in diameter.

Perfectly Round

Shell and Tire

Deformed Shell and Tire

Difference in diameters

Actual Top Clearance


Ovality and Brick Problems

Kiln shell ovality causes continuous flexing of the brick lining as the kiln turns.


Excessive ovality will damage the refractory lining, typically with scattered spalling and single brick fall-out among otherwise undamaged areas.

Ovality Refractory Damage


Shell Cracks Due to Ovality

Excessive ovality may cause longitudinal cracks in the shell beneath the tires.


Shell Cracks Due to Ovality

This shell crack was caused by excessive ovality. The heavy welding used to attach the support pad was a contributing factor.


Definition of Ovality

Dh

Dv

Absolute Ovality = Dh - Dv

Relative Ovality = (Dh – Dv )/D

Different definitions of ovality are in use. This definition takes into account both shell and tire deformation. Ovality is usually expressed in percent.


Relative Ovality

= 0

(shell is round)

Relative Ovality

> 0

(shell is deformed)

Relative Ovality


Ovality Limits

Ovality as a function of kiln diameter. Exceeding these limits will cause refractory and shell problems.


Heating the kiln up too fast can result in bottle-necking (pinching) of the shell inside the tire. Excessive heating, i.e., after loss of refractory under the tire, will also cause bottlenecking.

Causes of Excessive Ovality



Because of its massive size, the tire will change temperature more slowly than the shell. If the kiln is heated up too fast the shell will become restricted inside the tire and deformation will result.


After the shell becomes deformed and temperatures return to normal, there will be excessive running clearance and ovality, resulting in refractory damage.

Excessive Running Clearance



Measuring Ovality

The shell-test device measures the kiln shell’s actual radius of curvature during rotation. From this data the shell stresses can be precisely calculated.


Measuring Ovality


Measuring Ovality


Measuring Ovality

Shell-test device


Ovality (%) = 4D² x 100%

3dn

Ovality Calculation

D = outside diameter of the shell at the test location (meters)

dn = nominal inside diameter of the shell (mm)

= /15, deflection measured from the shell test diagram (mm)


Sample Calculation

Tire #1, Station #1, Downhill

ovality (%) = 4D² x 100%

3dn

ovality (%) = 4(3.727m)²(12mm/15) x 100%

3(3657.60mm)

ovality (%) = 0.406%

Ovality


Tire Creep and Top Clearance


Because of the slight difference in diameter between the tire ID and shell (support pad) OD, the shell rolls inside the tire as the kiln turns. This gives the appearance that the shell is “creeping’ inside the tire.

Creep


Place a chalk-mark on the tire and another right next to it on the shell. After one revolution, measure the distance between the two marks. This distance is the creep.

Measuring Creep

Creep


Creep is the difference in circumference. Therefore,

Measuring Creep

Creep

Creep

= Difference in Diameter


Top clearance depends on the difference in diameter and on the shell stiffness. The stiffness factor is normally between 1.5 and 2.0, depending on how thick the shell plate is.

Top Clearance

Top Clearance = Difference in Diameter x Stiffness Factor


Measuring Creep and Top Clearance

Top clearance and creep can be measured with this simple device.




This is a data sheet of 5 kiln revolutions. The distance between waves is the creep. The height of the wave is the top clearance. Always record tire and shell temperatures and identifying data (kiln no., tire no., date).







Correcting Ovality


Correcting Ovality

Excessive clearance can be removed with the installation of shims beneath the support pads.

Shims


Shim thickness is calculated to give a hot running clearance of about 3 mm (⅛”).

Correcting Ovality

Shim


If the kiln shell becomes deformed it is necessary to replace the tire section. Ovality can be reduced by installing temporary pads with filler plates, but bricks will never fit properly on the inside of the kiln shell.

Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Correcting Ovality


Tire Pad and Stop Block Repairs


Regularly inspect the supporting pads and stop blocks for weld cracks and repair at the next kiln stop. Waiting too long will only cause problems to compound.




Replace stop blocks when wear becomes excessive. Do not use shims as shown, as they probably won’t last.


Excessive stop block wear on the thrust tire is especially problematic since it can affect the gear’s position on the pinion.




Heavy welds directly on supporting pads frequently crack due to temperature fluctuations and fatigue stress. The floating pad design solves these problems.


Floating Tire Pad Design


Wear Ring Installation

Wear Rings

Anti-Rotation

Bars






Fractures at Shell Pads










Tire Crack Repair


Ultrasonic Inspection of Tires


Tire Repair Welding


Tire Repair Welding


Tire Repair Welding


Tire Repair Welding


Tire Repair Welding


Tire Repair Welding


Tire Repair Welding


Tire Repair Welding


Tire Repair Welding

Institute ™


Kiln Supports


Kiln Supports

Types of Kiln Supports Roller Adjustments Roller Inclination Roller and Tire Defects Roller and Tire Re-conditioning


Types of Kiln Supports


Rigid Kiln Support

A kiln support consists of two rollers with bearings mounted on a base frame. This rigid support is the most common.


Self-Aligning Kiln Support

Tire

Roller

Bearing

Hinge

Pivot Point

On this support the bearings are mounted on a pivoting frame.



A self aligning support maintains continuous contact between tire and roller as the kiln turns. As a result, there is less hertz pressure on the roller and components can be sized more economically.

Self-aligning support

Traditional Rigid Support




FLS Kiln Support Type SRB


FLS Kiln Support Type RA

FLS kilns have supports with self aligning bearings in spherical sockets.

Hornos FLS han soportes con cojinetes auto alineación en los zócalos esférica.


FLS Kiln Support Type RB

The RB support is similar to the RA support, except the bearing takes the thrust load next to the roller on a thrust ring.


Fuller Kiln Support

The Fuller support has rigid bearings.


Roller Adjustments


Axial Forces on a KilnLas fuerzas axiales en un horno

A kiln on a slope will tend to move downhill as it turns. That downward movement is resisted by both the friction force between rollers and tires, and by the force on the thrust roller.

Un horno en una pendiente tenderá a moverse hacia abajo a medida que gira. Ese movimiento hacia abajo es resistido tanto por la fuerza de fricción entre los rodillos y neumáticos, y por la fuerza en el rodillo de empuje

2 - 4% slope

Friction ForceLa fricción de la Fuerza

ThrustRoller Force

Kiln’s Downhill Force Horno de descenso de la Fuerza


Roller Friction Force Rodillo de la fuerza de fricción

When a kiln roller is not exactly parallel to the kiln axis, it imparts an axial thrust force to the kiln. The direction of this force (uphill or downhill) depends on how the roller is skewed, and on the direction of kiln rotation.

Cuando un horno de rodillos no es exactamente paralelo al eje del horno, que imparte una fuerza de empuje axial en el horno. La dirección de esta fuerza (hacia arriba o hacia abajo) depende de cómo el rodillo es sesgada, y en el sentido de rotación del horno.

Neutral

Neutral


Roller Adjustment Counter-Clockwise Kiln

Horno de rodillos de ajuste contra el sentido del reloj

To reduce the load on the thrust roller, all rollers should be skewed to push the kiln uphill, never downhill. Shown above are the correct adjustments for a kiln that turns counter-clockwise (looking from the burner floor).

Para reducir la carga en el rodillo de empuje, los rodillos deben estar sesgadas para impulsar el horno cuesta arriba, nunca hacia abajo. Arriba se muestran los ajustes correctos para un horno que se vuelve hacia la izquierda (mirando desde el piso del quemador).

Direction of Kiln ThrustDirección de empuje del horno


Roller Adjustment Clockwise Kiln

Ajuste de rodillos Las agujas del reloj del horno

Direction of Kiln ThrustDirección de empuje del horno

These are the correct adjustments for a clockwise turning kiln.

Estos son los ajustes correctos para un horno de las agujas del reloj girando.


Roller Adjustment Ajuste de rodillos

Rollers on the discharge pier are often adjusted for neutral thrust. This avoids excessive roller wear caused by dust from the kiln seal.

Rodillos en el muelle de descarga se han ajustado para el empuje neutral. Esto evita el desgaste excesivo de

rodillos causado por el polvo de la junta de horno.

Neutral

Neutral

Feed End

Discharge End


Good Roller AdjustmentBuen ajuste de rodillos

All Rollers Pushing Uphill

All Rollers Pushing Equally

Kiln Floating Between Upper and Lower Thrust Rollers (or, correct pressure on hydraulic thrust cylinder)

*Todos los rodillos empujar cuesta arriba*Todos los rodillos de presionar igualmente*Horno flotante entre el Alto y el Bajo rodillos de empuje (o, la presión correcta en el cilindro de empuje hidráulico)


Roller -Tire ForcesFuerzas rodillo-neumático

When the force on the tire/kiln is uphill, the force on the roller is downhill. The direction of thrust can be determined by observing the contact or gap at the thrust stop inside the bearing.

Cuando la fuerza en el neumático / horno es cuesta arriba, la fuerza sobre el rodillo es cuesta abajo. La dirección de empuje se puede determinar mediante la observación del contacto o la brecha en la parada de empuje dentro del rodamiento.

Direction of Kiln Thrust


Bearing Thrust Arrangements

FLS Type RA

Takes Thrust Load on Thrust CollarToma de carga axial de empuje del collar

FLS Type RB

Takes Thrust Load on Thrust RingToma de carga axial en el anillo de empuje

Fuller

Takes Thrust Load on Thrust WasherToma de carga de empuje en la arandela de empuje

UphillBearingTeniendo cuesta

arriba

Downhill Bearing

Teniendo descenso


Bearing Thrust ArrangementsTeniendo Régimen de empuje

FLS Type RA

FLS Type RB

Fuller

Contact

Contact

Contact

Gap

Gap

Gap

Direction of Force on Kiln

Dirección de la fuerza de Horno

Direction of Force on Roller

Dirección del Trabajo sobre rodillo


FLS Bearing Type RAFLS RA Tipo de cojinete

The RA bearing takes the thrust load on a thrust plate which is bolted to the end of the shaft.

El cojinete de la RA tiene la carga de empuje en una placa de empuje que se atornilla al extremo del eje.

Thrust Collar

De empuje del collar


FLS Bearing Type RA


FLS Bearing Type RB FLS RB Tipo de cojinete

The RB bearing takes the thrust load at a ring which is shrunk onto the shaft.

El rodamiento RB tiene la carga de empuje en un anillo que se contrae en el eje.

Thrust Ring

Anillo de empuje


FLS Bearing Type RB


Fuller Bearing

The Fuller bearing takes the thrust load on a thrust washer which is bolted onto to the housing end cover.

Thrust Washer


FLS Bearing Type RA

The direction of roller thrust in an RA bearing is determined by observing the gap between thrust plate and bronze bearing liner. Contact in the uphill bearing and a gap in the lower bearing indicates that the roller is pushing the kiln uphill.

La dirección de empuje del rodillo en un cojinete de la RA se determina mediante la observación de la brecha entre la placa de empuje y el revestimiento del cojinete de bronce. Contacto en el cojinete hacia arriba y una brecha en el rodamiento inferior indica que el rodillo está empujando hacia arriba el horno.


FLS Bearing Type RA

For FLS bearings type RA, there should always be contact between thrust plate and bronze bearing liner on the uphill bearing. This indicates that the roller is pushing the kiln uphill.

Para FLS tipo de rodamientos de la AR, siempre debe haber contacto entre la placa de empuje y el revestimiento del cojinete de bronce en el cojinete hacia arriba. Esto indica que el rodillo está empujando hacia arriba el horno.

Contact


FLS Bearing Type RB

Direction of roller thrust in an RB bearing is determined by observing the gap/contact between thrust ring and bronze bearing liner.


FLS Bearing Type RB

For FLS bearings type RB, there should always be contact between thrust ring and bronze bearing liner on the downhill bearing. This indicates that the roller is pushing the kiln uphill.

Contact

Thrust Ring

Bearing Liner


FLS Bearing Type RB

For FLS bearings type RB, a gap should always be present on the uphill bearing. This indicates that the roller is pushing the kiln uphill.

Gap


Fuller Bearing

For Fuller bearings, thrust direction is checked by rapping the bearing end cover with a hammer. A solid sound indicates contact, a hollow sound indicates a gap.


Measuring Roller Thrust

Important! Rollers and tire surfaces must be completely free of oil when skewing adjustments are made. Only graphite block lubrication is permitted.

Graphite Block


Rollers should be adjusted to “float” the kiln between the upper and lower thrust rollers.

Roller Adjustment


For kilns with hydraulic thrust rollers, support rollers are adjusted to keep the hydraulic pressure within specification.

Pressure Gage

Roller Adjustment


The force on the thrust roller can be calculated from the hydraulic pressure indicated on the gage.

Hydraulic Pressure

Force = Pressure x AreaArea = (Piston Diameter) 2 x

4


Calculation of Hydraulic Pressure When All Rollers Are Neutral

• Calculate the weight of the rotating parts of the kiln (shell, tires, gear, refractory, material load).

• Multiply by the % kiln slope to get the force on the thrust roller.• Divide by the total piston area of all thrust rollers.

Example:• 1000 short ton kiln x 2,000 pounds/short ton = 2,000,000 pounds• 2,000,000 pounds x 3% slope = 60,000 pounds force on thrust roller

• Area of single 10” diameter piston = (10) 2 x = 78.5 inches 2

4

Pressure = 60,000 = 764 PSI78.5


Roller Adjustment

Rollers are skewed by moving bearings in or out as required. Note that the adjusting screws shown are greased and wrapped to prevent corrosion.


Jacks for Roller Adjustment

Pancake Jacks are available with forces over 100 tons to aid in pushing bearings in for roller adjustment.


Roller Adjustment

Moving a bearing out is easier. A small jack may be needed.


• Always measure and record every bearing adjustment. To keep from changing the kiln center, make equal and opposite movements on each bearing.

Roller Adjustment



Measuring precise roller thrust is possible on FLS bearings using this “axial measuring device”.


The axial measuring device consists of a hand jack with pressure gage, a mounting fixture, and an adapter with bearing to enable readings when the roller is turning.




The jack is pumped up until the roller begins to move uphill off its thrust stop. At this point a pressure reading is taken and the reading is then converted to tons force.


FLS

Type RB

FLS

Type RA

Data assumes a jack piston with 16.6 cm2 surface area.



Caution! It may not be possible to accurately measure roller thrust if tire and roller surfaces are not cylindrical or if roller shafts or bearings are grooved.

Step-worn Roller and Tire Grooved Roller Shaft


Determining Roller ThrustTrial and Error Method

Find the roller’s neutral point (parallel to kiln axis) by adjusting the roller skew in small increments until the bearing thrust contact/gap changes from one bearing to the other.

Once the neutral point is determined, make a small adjustment to push the kiln uphill.

While making an adjustment of an individual roller, always observe the kiln’s thrust rollers to ensure that they are not being overloaded.


Roller Inclination


Roller Inclination

Just like horizontal skewing, vertical skewing of a roller, i.e., having a roller slope different than the kiln slope, will also create a thrust force.


Roller Inclination

Roller slope must not deviate from the kiln slope by more than 0.02% (0.04% for old kilns). The direction of allowable deviation must be such that the roller pushes the kiln uphill.


Measuring Roller Slope

Roller slope is measured with an inclinometer.


Inclinometer

100 mm Spacing

1 mm micrometer

scale

Due to its dimensioning, the inclinometer reads the percent slope directly.


Inclinometer

When the leveling bubbles are centered, the percent slope is read on the micrometer dial.


Inclinometer

Magnets allow mounting the inclinometer on horizontal or vertical surfaces. The inclinometer has a precision bubble level for each position.


Inclinometer

Check the roller slope with the inclinometer mounted on the shaft end. Take readings on both ends of the shaft and average them to eliminate the effect of roller shaft deflection.


Inclinometer

This arrangement can be used to measure the roller slope while the kiln is turning.


Inclinometer

Using an inclinometer on a precision straight edge across a kiln base to determine the correct slope.


Roller and Tire Defects


If kiln rollers are skewed too much the wear rate can be quite severe.

Tire and Roller Defects


Excessive hertz pressures on under-designed or poorly cast tires and rollers can result in severe pitting.



The old practice of running a roller in a water bath is now thought to promote surface pitting and is no longer recommended.




When rollers are misaligned or conical-shaped, the kiln load is spread over too small an area. This causes high surface stresses resulting in pitting.

Cuando los rodillos están desalineados o de forma cónica, la carga del horno se extiende sobre la zona son demasiado

pequeñas. Esto hace que la superficie de alta tensiones resultantes de las picaduras.



A defect on a roller may transfer to the tire, and vice-versa.

Un defecto en un rodillo puede transferir a la llanta, y viceversa



Roller or tires may wear to a conical shape.

Rodillo o llantas pueden llevar a una forma cónica



A tire running off the roller for a long time will wear into a step pattern.

Un neumático corriendo el rodillo durante mucho tiempo se gastará en un paso patrón



Tire wobble can create a concave roller surface.

Bamboleo de neumáticos puede crear una superficie del rodillo cóncavo


Roller and Tire Re-conditioning



Rollers and tires may be re-conditioned by machining or grinding. Shown above is a lathe adapted for this purpose.

Rodillos y los neumáticos pueden ser re-acondicionado por maquinado o esmerilado. Arriba se muestra un torno adaptados para este fin.



Rollers are re-conditioned while the kiln is in operation.

Los rodillos son re-acondicionado, mientras que el horno está en funcionamiento



Machining a kiln tire while the kiln is in operation.

Mecanizado de un neumático del horno, mientras que el horno está en funcionamiento



The machinist is protected with a heat shield.

El maquinista está protegido con un escudo térmico



This roller is being resurfaced by grinding rather than machining.

Este rodillo se resurgido por desgaste en vez de mecanizado



Re-surfacing a tire by grinding

Re-pavimentación de un neumático por desgaste


Tire and roller edge defects must also be removed. Edges should then be chamfered.


Institute ™


Kiln Bearings

Institute ™Kiln BearingsIntroduction 286

Kiln Bearings

FLS Bearing Type RA - 1958 Design

FLS Bearing Type RB - 1974 Design

Fuller Bearing



FLS kilns have supports with self aligning bearings in spherical sockets.


FLS Bearing Type RA

Spherical Socketwith Water Jackets

Heat Shield

Bronze Bearing

Liner

Thrust Plate

Oil Scoop

Oil TrayOilScraper

Oil Level Gage

Felt Oil Seal


FLS Bearing Type RA

Stop Block

Water Piping

Inspection Port

Heat Shield


Type RA Oil Seal and Scraper

Rubber Oil

Scraper

Felt Seal


FLS Bearing Type RA


Inspection Ports

Oil FlowOil Flow

Thrust Contact/Gap

The FLS type A bearing has three inspection ports for monitoring lubrication and thrust direction.


Oil Tray

Oil scoops dip into the sump and carry oil into the oil tray. Holes in the tray allow oil to drip onto the shaft. The tray slope is adjustable to permit downhill flow of oil.

Tray

Scoops

Slope Adjusting

Screws


FLS Kiln Support Type RB

The RB support is similar to the RA support, except there is no thrust plate and the bearing takes the thrust load on a thrust ring.

Thrust Ring


FLS Bearing Type RB

Oil Scoops

Oil SealAdjustable

Oil Tray

Bearing Base

End Cover with

Inspection Door

Spherical Socket with Water Jacket

Bronze Bearing Liner

Thrust Ring


FLS Bearing Type RB

Heat Shield

Inspection Port

Water Piping

Oil TrayTemperature

Detector

Dowel Pin

Retainer Clamp


The RB bearing has a split rubber oil seal which requires monthly greasing.

Grease Fitting

Type RB Oil seal


FLS Bearing Type RB


Fuller Kiln Support

The Fuller support has rigid (non-spherical) bearings.


Fuller Bearing

Thrust Washer

End Cover

Inspection Port

Oil Tray

Oil Scoop

Oil Level Indicator

Bronze Bearing Liner


Bearing Liners


FLS Bearing Liner Details


Liner Clamps

Liners and sockets are clamped to prevent from rotating out of the housing.


Liner Clearance

Liner side clearances should be checked with a feeler gage at all four liner corners after installing a new liner.

http://www.handsontools.com/store/show_product/?product_id=24186



Bearing Tolerances


Bearing Tolerances

Side Clearance

Oil Film

Insufficient side clearance will prevent oil from being drawn into the bearing. Excessive side clearance will result in the load being spread over too small an area, with a reduction of the oil film thickness at the bottom of the shaft.


Checking Liner Contact

Before installation of a new liner, apply Prussian blue to the shaft to check liner to shaft contact. The liner, installed in the socket, is lowered onto the shaft and slid back and forth longitudinally to pick up the dye at the liner contact points.



A well-fitting liner will pick up the blue only in the center down its entire length.



This liner shows less than full contact along its length, indicating a high spot in its center.



High spots are removed by scraping the bronze away at the heavily blued areas.


Bearing Lubrication

Institute ™

Lubrication Film

Tiny surface asperities are kept from contacting each other by a good oil film.

Institute ™

Hydrodynamic Lubrication

As one surface slides over another, a wave of oil wedges them apart, creating an oil film.

Institute ™

Hydrodynamic Lubrication

When the shaft rotates, oil is drawn in between the journal and bearing. The shaft lifts and a lubrication film is established.

Institute ™

Elasto-hydrodynamic Effect

Under extreme forces, plastic deformation occurs and surface area in the contact zone increases. Lubricant viscosity multiplies under extreme pressure. The result is a thin but stable oil film capable of keeping surfaces separated.

Institute ™

Boundary Lubrication

When speed or oil viscosity is too low, or when loads are excessive, surfaces may contact. Boundary lubrication conditions are said to exist.

Institute ™

EP Additives

Extreme pressure and anti-wear additives in the oil react to the high heat and pressures at the surfaces to form a low-friction chemical film, thus preventing surfaces from seizing.


Oil Film Thickness

Oil film thickness increases with viscosity and speed and decreases with load. A good film thickness is three times the surface roughness.

L =


Viscosity

Viscosity, or the resistance of a liquid to flow, is the most important property of lubricating oil. Oil viscosity changes drastically with temperature.


Viscosity

Oil viscosity is selected based on equipment operating temperature range.


Viscosity Index

Viscosity index is a relative measurement of how viscosity changes with change in temperature. Oil with a higher viscosity index can maintain its viscosity over a wider temperature range.


ISO Viscosity Grade

• International Standards Organization designation for oil viscosity grade.

• Measured as Centistoke (cSt) at 40º C.

• Becoming more common than SSU (Saybolt Seconds Universal).

• Multiply ISO VG by 5 to approximate SSU at 100º F.


Viscosity Equivalents


Kiln Bearing Lubricants

• Gear oils with EP additives

• Viscosity ambient temperatureISO VG 460 below 5º CISO VG 680 above 5º C

• Synthetic oils are preferred over mineral oils, due to their increased viscosity index, lower pour point and effectiveness at high temperatures.


Oil Level Indicator

Check oil level daily. Note that the level in the uphill bearing indicator is different than in the downhill bearing. Make sure that the oils scoops dip into the oil.


Inspection of Oil Flow

At start-up, especially after a long shutdown, oil is added manually to ensure that there is lubrication before rotation starts.


Bearing Lube Pump

Bearings can be equipped with lube pumps to provide oil to the tray prior to kiln start-up.


Bearing Circulating Lube System

A circulating lube unit can filter and cool the bearing oil. This one-pump unit serves one kiln support. It is equipped with four flow switches, one for each bearing of the two-roller support.


Bearing Temperature RTD

Oil film temperature can be measured with an RTD (resistance temperature detector), which slides over the journal as the shaft turns. Temperatures above 80ºC indicate a lubrication problem


Hot Bearings

Check cooling water supply. Check that a bearing heat shield is in place. Check oil cleanliness. Check the oil viscosity. Switch to a higher viscosity

(ISO V.G. 1000) if oil temperature exceeds 80-90ºC. Use synthetic oil instead of mineral oil. Check thrust load and reduce by adjusting roller

skew accordingly. Check liner smoothness. Replace if necessary. Check shaft smoothness. Re-machine if necessary. Check liner to shaft contact.


Lubrication Failure


Lubrication Failure


Severe Lubrication Failure


Catastrophic Lubrication Failure










Rigging


Rigging for Fuller Roller Assembly


Rigging for Fuller Bearing

“Feed End” Stamp


Bearing End Cover Removal

Bearing inspection can be facilitated by the preparation of two 24” rods on which to slide off the end cover.


Rigging for FLS Bearing Liner



Warning! Do not use cover lifting eyes to lift FLS bearings. They are designed only to lift the covers off the bearing housing.

Lifting Eyes for Cover Only!

Institute ™


Kiln Drive


Kiln Drive

Gear and Pinion Drive

Friction Drive

Hydraulic Friction Drive

Coupling Basics


Gear and Pinion Drive

Reversible Pinion

Jack Shaft

Main Reducer

Tandem Variable Speed Motors

Tacho-meter

Motor Cooling Fans

Fixed Bearing

Free Bearing


Kiln Inching Drive

Backstop

Inching Drive Reducer

One-way Clutch

Inching Drive Motor

The inching dive arrangement permits a rotation of approximately once every 10 minutes. A one-way clutch prevents over-speeding when the main drive is in operation. A backstop prevents kiln roll-back.


Kiln Drive

A jackshaft is used to improve the layout of the drive pier. This one is equipped with gear couplings.


Pinion Alignment

The pinion must be positioned so that pitch circles are tangent, and there is full face contact across the width of the teeth.

Pinion Pitch Circle

Gear Pitch Circle


Axial Alignment

The gear and pinion must have full face contact when the kiln is hot. It may be necessary to move the thrust rollers or reposition the thrust tire stop blocks to achieve this.


Inching Drive

Main Reducer

One-Way Clutch Backstop

Inching Drive

ReducerInching Motor


One-Way Clutch

The one-way clutch prevents over-speeding of the inching drive by locking the input and output shafts in one rotational direction only.


One-Way Clutch

Automatic Transmission

Fluid

Most one-way clutches have locking steel pawls inside, which require lubrication with automatic transmission fluid only.


Kiln Rollback

•Due to the feed material being dragged up one side of the kiln as it turns, an offset load exists which tries to make the kiln rotate backwards.

Load Center of Gravity


Backstop

The backstop prevents kiln roll-back. Most backstops aslo have locking steel pawls inside, which require lubrication with automatic transmission fluid.


Backstop

The backstop can be released manually to allow the kiln to roll back. Warning! Rolling back too fast can over-speed and destroy the inching drive. Keep a lock on the release switch to prevent unauthorized use.

Safety Padlock

Release Switch


Pinion Bearing Oil Lubrication

Bearing oil level should be sufficient to cover half of the lowermost rolling element. Note that the indicator may show different levels, depending on whether it is mounted on the uphill or downhill side of the housing.

Oil Level Sight Glass


Pillow Block BearingStabilizing

Ring for Fixed Bearing only

No Stabilizing Ring for Free

Bearing

Oil Level


Kiln Drive

This drive arrangement has a jack shaft with flexible disc couplings. The backstop is integrally mounted on the inching drive reducer.


Friction Drive


Friction Drive

Motors turn the rollers, and friction between rollers and tires turns the kiln. There is no kiln gear. Friction drive is used only on new two-support kilns.


Friction Drive

Both rollers are driven. The motors are balanced to prevent slippage.


Friction Drive

The reducer is shaft mounted. The inching drive with integral backstop is mounted directly on the main reducer. The main motor is coupled with a Cardan shaft. The inching drive motor has a fluid coupling.


Friction Drive

A special torque arm is used to prevent reducer rotation while still permitting movement of the roller shaft.



A friction drive may use a hydraulic motor to turn the rollers.


Hydraulic Drive

Advantages

High starting torque

High degree of controllability

Even load sharing between rollers

Space savings

No reducer necessary (when using radial piston motors)

Shaft mounted, simplified foundation



This hydraulic drive uses an axial piston motor and a planetary reducer mounted on the roller shaft.



Shaft-mounted planetary reducer with torque, with integral hydraulic motor and inching drive.



This hydraulic drive uses four radial piston motors mounted directly on the roller shaft.


This Hagglunds radial piston motor develops extremely high torque, and a reducer is therefore not needed.




The load is equally shared and each roller receives the same power and torque.



The typical kiln drive will have multiple pumps for increased efficiency.



Hydraulic drive power curve.



DC drive power curve.



Hydraulic drive power losses.



DC drive power losses.


Couplings


Coupling Alignment

Couplings must be precisely aligned to minimize parallel and angular misalignment.


Coupling Alignment

Imprecise alignment will cause shock and vibrations to be transmitted to motor and machine bearings, resulting in reduced bearing life and possible equipment damage.


Coupling Alignment

Couplings are usually aligned with a dial indicator.


Coupling Alignment

Align the coupling as accurately as possible to promote long bearing life (not just to within coupling manufacturer’s specs).


Coupling Alignment

The coupling gap can be checked with a feeler gage. Gap specifications are normally found on the equipment foundation drawing, or in the coupling manufacturer’s data.

Feeler Gage


Institute ™

Laser Alignment

Laser alignment offers the most accurate and easiest coupling alignment.


Laser Alignment

A laser beam on one coupling half reflects back onto a sensor from a mirror on the other half. Misalignment is read on a hand-held computer.


Laser Alignment

Aligning a kiln inching drive with laser alignment method.

Institute ™


Kiln Alignment


Alignment Principles

Internal Alignment

Hot Kiln Alignment

Kiln Alignment


Alignment Principles


Kiln Alignment

A kiln is considered aligned when the center of rotation of the kiln shell at every support lies on a straight line.


Kiln Alignment

Note that a kiln with only two supports is always aligned, as there is always a straight line between two points.

Two Support Kiln


Kiln Alignment

A kiln can be misaligned in the horizontal or in the vertical plane.

Horizontal Axis

Vertical Axis


Consequences of Misalignment

Misalignment changes the loading on the kiln supports and causes overstressing of the shell and supports.

3597 kN 7048 kN 2815 kN

3902 kN 6491 kN 3067 kN

10 mm


Misalignment can result in all of the load being concentrated on one roller.

Consequences of Misalignment


Internal Alignment


Internal Alignment

Internal alignment is normally used when assembling a new kiln. A line of sight is shot through batter boards marking the kiln centers at the shell section ends and at the tire locations.


New kiln sections usually have steel spider bracing with precisely marked centers. If not, wooden batter boards can be prepared.

Internal Alignment


Internal Alignment

The kiln shell’s center is found by scribing four arcs on a target card tacked onto the batter board.


Internal Alignment

Drawing diagonals at the arcs’ intersections will locate the center.


Internal Alignment

Removable targets with marked shell centers are placed at each tire center and shell end. The theodolite’s line of sight is marked on the target and the offset is measured.


Kiln Alignment

Note that if there is any top clearance present, the tire center is not the same as the kiln center. Alignment calculations must take hot running clearance into account.

Tire centre

Kiln centre

S

Top Clearance


Roller Adjustment

Field Joint Adjustment

After measurements are taken the kiln is aligned by adjusting rollers and field joints.

Correcting Misalignment



Moving both rollers horizontally will move the kiln center by the same amount.

h

h

h


Roller adjustments to correct vertical alignment can be calculated from the relationship of right triangles.

A

B

C

B

C

A2 + B2 = C2




Moving one roller horizontally will move the kiln center horizontally by half and vertically by one quarter (approximately) of the distance.

1

½

¼



Caution! Moving a roller on the piers immediately uphill and downhill from the kiln gear will affect the gear alignment.


Hot Kiln Alignment


Measurements and corrections can be completed while the kiln is operating.

The data collected indicates the real conditions as the kiln is operating.

Alignment errors can be corrected immediately or during a planned kiln outage.

Advantages

Hot Kiln Alignment


Mechanical Hot Kiln Survey Method

Laser Kiln Survey (LKS) Method

Hot Kiln Alignment


Diameter of support rollers and live rings using electro-mechanical instrument.

Temperature of the support rollers, live rings and kiln shell.

Creep and clearance between the kiln shell support pads and live rings.

Both methods utilize a variety of measured data to determine kilns axis:

Hot Kiln Alignment


Using a theodolite to establish a line of sight along the kiln, the horizontal distances from the line of sight to each support roller is measured.

Mechanical Alignment

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Using an optical level the elevations of the bearing base frames are determined.


s

f

j

F

a b

cq

cleft cright

Tire centre

Kiln centre

dleft dright






Elevation markers on kiln piers should be checked to see if a kiln pier has sunk.


Elevation Markers













Roller and Tire Circumference

Using a precision measuring wheel and tachometer the circumference of the roller and tire are measured.


DIGITAL CIRCUMFERENCE OF TIRE

A magnet and magnetic sensor record start/stop positions. Circumference is read on the digital readout to 0.1 mm accuracy.

Magnet

Roller and Tire Circumference


Line of sight

Using the measurements, and knowing the distance between supports, a kiln centerline can be constructed which best fits the existing roller positions.



s

f

j

Fa b

cq

cleft cright

dleft dright



Laser Kiln Survey

Tire elevation and location can be determined utilizing a laser theodolite from ground level.


Laser Kiln Survey

Laser measurement provides the most accurate method of kiln alignment.

Kiln Center Tolerances

Horizontal Plane 1.5 mm

Vertical Plane 2.5 mm


Laser Kiln Survey


Laser Kiln Survey


Laser Kiln Survey


Laser Kiln Survey


Questions?

Institute ™


Kiln Miscellaneous


Kiln Inlet Seal

Kiln Outlet Seal

Thrust Roller

Hydraulic Thrust Roller

Kiln Maintenance Checklist

The Good Old Days

Kiln Miscellaneous


Kiln Inlet Seal


Kiln Inlet Seal

The kiln seal prevents cold air from entering the process and driving up fuel costs. The seal must remain tight while accommodating kiln run-out and longitudinal movement.


Kiln Pneumatic Inlet Seal

The pneumatic seal consists of two sliding surfaces pushed together by pneumatic cylinders.

Pneumatic Cylinders


Kiln Inlet Seal

Spring Loaded Graphite Plug

Seal Detail

Pneumatic Cylinders


Kiln Inlet Seal Detail

Graphite Seal Cord

Wire Rope

Graphite Plugs

Rotating Kiln Shell

Rotating Sealing Surface

Stationary Sealing Surface

Sliding Contact

Stationary Kiln Inlet Hood


Kiln Inlet Seal

The seal is suspended by a carriage which allows it to move longitudinally as the kiln expands and contracts.

Carriage

Turnbuckle


Pneumatic Inlet Seal

The pneumatic cylinders, when pressurized, will press the two seal halves tightly together.

Stationary Seal Half

Rotating Seal Half


Filter, Regulator, Lubricator

Cylinder force is controlled by adjusting the air pressure. A lubricator prevents cylinder corrosion and seize-up. The filter keeps condensation and dirt out of the cylinder.


Filter, Regulator, Lubricator


Kiln Inlet Seal

The seal’s sliding surfaces are graphite lubricated.

Spring Loaded Graphite Plug

Graphite Plugs in Seal Plate


Kiln Inlet Castings

Castings on the inlet hood and kiln inlet cone keep the castable refractory in place. Inspect them at annual shutdown.


Spring Plate Inlet Seal






No, covering the spring plates with plastic won’t help.



Outlet Seal


Kiln Outlet Seal

The spring plate outlet seal has become the outlet seal of choice. The seal can withstand the harsh conditions at the kiln hood.


Kiln Outlet Seal

Spring Plate Wire Rope


Kiln Outlet Seal

Counterweight

Spring plates are wrapped with a counterweighted wire rope arrangement to keep them tight against the cowl.


Forced Air

Cooling

Kiln Outlet Seal

A stainless steel cowl at the kiln outlet provides an air channel for cooling of the kiln discharge castings and the spring plate contact surface.


Kiln Outlet Seal

Spring plates are bolted on and are easily replaced.


Kiln Outlet Seal

Dust from kiln hood puffing falls down the chutes to the drag chain conveyor or into the clinker cooler.

The Old Way The Better Way


Kiln Outlet Sector

The kiln nose rings sees severe service and must be regularly inspected for refractory and casting failure.


Kiln Outlet Seal

This alternate spring plates design features outwardly protruding spring plates.


Kiln Outlet Seal

Outwardly protruding spring plate design.


The Most Expensive Seal

A bad seal allows cold air into the kiln. The cost of extra fuel to heat this cold air can amount to tens of thousands of dollars per year.


Thrust Roller


Thrust Roller Assembly

Oil Seal

Oil Level Pipe

Spherical BearingsTie

Rod

Tire

Shims

Clearance

Keep the clearance to a minimum (6mm), and adjust the shims to keep the kiln gear in proper longitudinal alignment.


Thrust Roller Assembly

Set Screws

The kiln position can be controlled by adjusting set screws on this thrust roller base.


Thrust Roller Position

Stop Ring

Thrust Tire

The thrust roller is positioned to maintain proper hot running alignment between kiln gear and pinion. Repositioning may be necessary as stop rings wear.


Thrust Roller Misalignment

A misaligned thrust roller will result in vertical forces on the roller as shown above.

Roller Tilted to Left Roller Tilted to Right

Roller Offset to Left Roller Offset to Right


Thrust Roller Misalignment

An improperly aligned thrust roller can ride out of its socket, causing damage to tire stop blocks.


Thrust Roller

Thrust rollers can become overloaded if the kiln’s supporting rollers are improperly skewed. This thrust roller base became deformed from excessive force.


Fuller Thrust Roller


Fuller Thrust Roller





The hydraulic thrust roller maintains a constant, controlled force on the thrust tire and keeps the kiln in an electronically determined position.



Guide BarHydraulic Cylinder

Position Sensor



Breather

Oil Level Sight Glass

Guide Bar Grease Fittings

The spherical bearings are lubricated with ISO VG 1000 gear oil. Guide bars are grease lubricated.


Thrust Roller

The roller surface is graphite lubricated.




Hydraulic Cabinet

The hydraulic power unit is normally placed beneath the kiln’s thrust pier.


Hydraulic Cabinet

Accumulator

Pump

Directional Valve

Relief Valve

Tank


Hydraulic Pump

The axial piston pump has manual adjustments for pressure and flow rate.


Directional Valve

A directional valve directs fluid to the thrust cylinder, or allows the cylinder to bleed down.


Hydro-pneumatic Accumulator

An accumulator stores hydraulic energy. It is used to maintain a steady force on the thrust tire even though the tire wobbles slightly as the kiln turns.


G as Valve

B ladder

Shell

Port

Anti-ExtrusionValve

Nitrogen G as

Fig ure 17.6 Bla d d e r-Typ e Ac c um ula to r

CO PYRIG HT (1999) VICKERS, INCO RPO RATEDC


The accumulator contains a rubber bladder which is charged with nitrogen gas.


psig0

500

1000

1500

2000

psig0

500

1000

1500

2000

psig0

500

1000

1500

2000

System PressureLess Than p precharge

System Pressureat p m ax

System Pressureat p m in

Fig ure 17.7 Bla d d e r Ac c um ula to r O p e ra tio n

C O PYR IG HT (1999) V IC KER S, INC O R PO R ATEDC


When hydraulic pressure increases and decreases the gas is compressed and expanded.



The accumulator is pre-charged with nitrogen to approximately half of the expected average operating hydraulic pressure.

Danger!

Do not charge with air or oxygen!


Pressure Relief Valve

A pressure relief valve limits hydraulic pressure in the system. This prevents excessive downhill kiln force from damaging the thrust roller.


Hydraulic Filter

An in-tank filter with a 10 micron element keeps hydraulic fluid clean. The protruding red button indicates the element needs changing.


Thrust Cylinder LVDT

An LVDT (linear variable differential transformer) mounted in the hydraulic cylinder measures the distance that the cylinder rod is extended.


Thrust System LVDT Cabinet

The LVDT signal goes to a cabinet where the kiln’s hot running axial position is set and where alarms are programmed for excessive uphill and downhill kiln position.


Fuller Hydraulic Thrust Roller


Fuller Hydraulic Thrust Roller


Preventive Maintenance Checklist


Daily• Thrust Roller

• Kilns with one thrust roller (mech. or hyd.)– visual check of the thrust rollers including

recording of the thrust pressure (ideal 500 psi, can vary from 200-800 psi). Maximum design pressure is 1200-1300 psi

– check the temperature of the thrust roller housing and face.

• Kilns with two thrust rollers– Observe the kiln position relative to the uphill or

downhill thrust rollers– Check temperature of the housing and thrust roller

face if there is constant contact.


• Seals

• Visually check feed and discharge seals

• Gear

• Visually check the gear and pinion

• Rollers and Live Rings

• Visually check all roller and tire surfaces

• Lubricate contact faces between tires and shell mounted tire pads and stop blocks using a mixture of graphite powder and water.

Daily


• Temperatures

• Record kiln shell temperatures and include a night visual inspection for “hot spots”

Daily


Weekly

• Check and record direction of thrust on all rollers.• Check lubrication on all support rollers.• Check oil levels in support roller bearings and

thrust roller bearings.• Check and record the tire creep and clearance.• Record related shell and tire temperatures.• Check condition of tire stop blocks and wear rings.


• Check general condition of kiln shell.

• Check contact patterns between gear and pinion by observing the oil smear on the contact face for at least one full kiln rotation.

Weekly


Annually

• Perform complete check of kiln alignment utilizing the laser or mechanical alignment method. Kiln alignments should be completed after major repairs have been made to the kiln.

• With this information recorded and compared, a problem should be caught before a real dilemma occurs (i.e. an unplanned shutdown).

• Prior to planned kiln shutdowns, an extensive mechanical inspection should be completed to determine repairs required.


The Good Old Days


The Good Old Days


The Good Old Days


Rivets


Don’t Be Mean to Your Kiln

Date post:	02-Dec-2015
Category:	Documents
Upload:	ronald
View:	65 times
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1.Hornos Rotatorios

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